Insulated glass is heavily utilized in modern residential and commercial construction. In many areas of the country it is required by building code as an energy conservation measure. A single pane of glass alone has very little insulating value. Multi-pane insulated glass windows have much greater insulating value. Insulated glass units generally include at least two panes of glass having identical shapes. Sealants and adhesives are used to bond the glass panes to a perimeter spacer which separates the two panes of glass. The entire perimeter including the two panes of glass and the spacer are sealed to one another to eliminate movement of ambient air into the space between the two panes of glass.
The space is filled with dehydrated air or more commonly another gas such as argon, xenon or krypton. Sulfur hexafluoride is also used for gas filling. The filling of insulated glass units with argon or another gas that is not air has been found to increase the energy efficiency of the insulated glass units markedly. Some insulated glass units includes three panes of glass with two intervening spaces which are similarly filled with argon or another gas other than air and then edge sealed.
The spacer in an insulated glass unit is inset from the peripheral edges of the glass panes leading to a trough shaped space bounded on two sides by the glass panes and on one side by the spacer. In the manufacturing of some insulated glass units, this space is filled with an adhesive sealant which forms the, so called, secondary seal of the insulated glass unit.
Recently, other primary sealing technologies have been developed. These edge sealing technologies utilize a primary seal that stands alone and produce an insulated glass unit that does not include a secondary seal. This may result in faster production and reduced cost for insulated glass units though the units may also have shorter lives and be useful in a narrower range of climatic conditions.
If present, the secondary seal may be applied using a variety of different adhesive sealants. These include time setting sealants, such as silicones or butyl rubber sealants. Sometimes two part sealants utilizing a resin and a catalyst to polymerize the resin are utilized. More commonly in modern manufacturing, hot melt adhesive sealants are used. Hot melt adhesive sealants are general applied in a liquid state at a temperature of approximately 350° F. and harden upon cooling to ambient temperature.
In high volume manufacturing facilities, the secondary seal is commonly applied by fully automated equipment in which a computer controlled robotic sealant applying head is moved around the peripheral edges of the insulated glass unit under computer control and applies the sealant to the edge or edges of the insulated glass unit. Fully automated secondary edge sealing equipment of this sort can apply the secondary seal to very large numbers of insulating glass units in a production run. Typically, the insulated glass units in these circumstances are produced in large runs of identical units.
The process of manufacturing insulated glass units generally includes infeed of glass panes or lites into a washing unit that cleans both surfaces of each pane and, in particular, the surface of each pane that will be on the interior of the insulated glass unit. This is particularly important because, once the insulated glass unit is complete the interior surfaces will be inaccessible to cleaning and any visible dirt is impossible to remove. Accordingly, the washing station is generally followed by an inspection station to assure that the panes are clean.
In the prior art, panes or lites are then conveyed in tandem fashion to further processing. The panes are divided into pairs, each pair including a spacer lite to which a peripheral spacer is applied and which forms the back of the IGU and a topping lite which will ultimately be applied on top of the spacer lite and sealed to the spacer to form the insulated glass unit. According to the prior art generally, the topping lite proceeds first in the pair and is followed by the spacer applied lite. When the spacer lite reaches a spacer application station the peripheral spacer is applied. The spacer lite and the topping lite are both advanced so that the topping lite can be removed from the conveyor. According to the prior art, the topping lite is picked up first at the gas press then the spacer applied lite is conveyed in and unit is gas filled and assembled. The primary sealed insulated glass unit is then conveyed to a secondary seal applicator to apply secondary sealant to the edges bordered by the spacer and the peripheral portions of the lites. The completed IGU is then conveyed to the end of the processing line for transport to next steps.
According to the prior art, the heads for application of spacer and sealant are stationary in the X axis and the glass lites or IGUs are moved relative to the fixed heads. Thus the prior art requires that the glass to move though the zone three times. Once for application along bottom x axis moving forward, once across the top x axis moving backward and then removal forward to the next station.
There is a need for application devices in the window industry that can increase the productivity of manufacturing of insulated glass units.